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- A fatal brain disease is spreading in deer and elk...
and hunters are dying from a very similar illness.
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- The disease that struck the three hunters is ominously
similar to another disease that's spreading in deer and elk in Colorado
and Wyoming. This possible connection has some people pointing to deer
meat and crying killer.
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- The accusation could prove true. The disease found in
deer and elk is called Chronic Wasting Disease (CWD), and it's closely
related to Creutzfeldt-Jakob Disease (CJD), which is what killed the hunters.
Both CJD and CWD are classified as "transmissible spongiform encephalopathies"
(TSE). Diseases don't always make the leap from one species to another,
but there is a connection between chronic wasting disease and Creutzfeldt-Jacob
that has many scientists concerned: Another TSE-bovine spongiform chronic
encephalopathy (BSE)-spread from cattle to humans in the United Kingdom,
where it was dubbed "Mad Cow Disease."
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- Mad Cow Disease exploded in U.K. cattle herds in the
late 1980s and early '90s. But it was not until 1996 that it was found
to have crossed over to humans. Since then, 43 people are known to have
died in the U.K. from Mad Cow Disease, but because of its long incubation
period-possibly up to 20 years-it may yet kill many more. The disease resulted
in European bans on British beef and forced the destruction of more than
half of the cattle in the U.K.
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- Because of the similarity, CWD has already been nicknamed
"Mad Deer Disease," but it hasn't yet proved as sinister. In
fact, another TSE called "scrapie" has afflicted sheep for at
least 250 years and has never been found to cross over to humans. Still,
because of Mad Cow Disease, CWD is hitting the hunting world like a horror
movie monster, lurking unseen in the shadows.
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- Scientists, however, are on the monster's trail. More
than a dozen states and the federal Centers for Disease Control (CDC) in
cooperation with the Animal Plant Health Inspection Service (APHIS) are
pouring money and resources into a thus-far-quiet, but nevertheless massive,
investigation. They're trying to answer two questions: Is CWD killing people?
And where is CWD?
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- To answer the first question, the CDC is taking a street
cop approach by chasing down every lead that comes into its Atlanta headquarters.
And with what they've found so far, this horror movie is starting to feel
more like an X-File. Larry Schonberger, a medical epidemiologist for the
CDC, says, "I've sent one of our epidemiologists out to investigate
to see if there's a link between CWD and the [three] hunters' deaths. I
did this because two of the victims were young [one was 27 years old, the
other 30]. That's very unusual. CJD normally shows up in people well over
30. But our scientist's initial report is that the deer eaten by the victims
had not come from [known] infected areas. But we're taking no chances.
In fact, a young girl died in a southern state from CJD who had reportedly
eaten venison that her father had shot in Maine, so this year 300 deer
will be checked for the disease in Maine.
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- "At this point we can't rule out a link between
Chronic Wasting Disease and the hunters' deaths, but I think it's unlikely.
CJD occurs all over the world at a ratio of about one in 1 million people.
Each year in the U.S. 250 to 300 people die from CJD. So it's understandable
that a few of the victims happened to have eaten venison," says Schonberger.
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- Meanwhile, APHIS and many state agencies are doing a
broader search to discover if CWD can be found outside known infected areas,
and to find out how fast it's spreading from the infected area. Since there
is no accurate test that can be performed on living animals, scientists
are checking brain samples. The samples are collected at deer check stations
and meat processors. From there they are sent to a number of labs for analysis.
Colorado and Wyoming each check thousands of samples annually at their
own research facilities, but other states, such as Nebraska, South Dakota,
Montana and Nevada, send their samples to the APHIS lab in Ames, Iowa.
So far no wild deer or elk outside of Wyoming and Colorado have shown up
with the disease. CWD has been found in elk produced in the game-farm industry,
however.
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- Both CDC and APHIS efforts are designed simply to get
a fix on the situation. Right now not much can be done to stop or prevent
Mad Deer Disease because scientists know so little about it. To get answers,
however, labs worldwide are intensively studying all spongiform encephalopathies.
The CDC, for instance, is investigating this group of pathogens at its
Prion Disease Pathology Surveillance Center at Case Western Reserve University
in Cleveland. But despite the intensive research efforts, answers are slow
to come.
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- In fact, scientists don't even agree on what causes TSEs,
although there is wide support for a theory put forth by Stanley Prusiner,
M.D., a professor of neurology at the University of California at San Francisco,
whose research won him the Nobel Prize in Medicine in 1997. Prusiner theorizes
that "prions" (proteinaceous infectious particles) cause this
family of diseases, and not a virus, as was previously assumed. His chief
reason for fingering "rogue proteins" is that the chemical and
physical procedures that destroy most viruses don't affect TSEs, whereas
procedures that have been found to degrade proteins seem to inactivate
them. Prusiner's hypothesis is that prions kill by turning normal proteins
in nerve cells into infectious ones by forcing them to alter their shape.
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- A Doomsday for Deer? In light of the recent conjecture
about CWD killing humans, it's easy to overlook one certainty about this
disease: It kills deer. The ramifications of that indisputable fact are
almost as unsettling. Before we go on, keep three things in mind: CWD is
spreading, CWD is always fatal and CWD has no known cure.
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- In the infected areas of Wyoming and Colorado, about
4 to 8 percent of deer and 1 percent of elk have the disease, according
to Beth Williams, a professor of veterinary services with the University
of Wyoming, and Mike Miller, a biologist with the Colorado Division of
Wildlife.
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- "It's been spreading slowly since it was first found
in the wild in 1981," Williams says. "We think [CWD] passes from
animal to animal through bodily fluids. So it probably takes physical contact
of some kind to pass the disease."
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- That said, the spread of CWD may soon pick up speed because
whitetails may be next on its hit list. Thus far the disease has mostly
spread in mule deer up the South Platte drainage in northeastern Colorado.
Mule deer have fairly thin population densities along the river, but whitetails
have heavy population densities in this area. This dilemma has Miller worried
because the whitetail's heavier population density means there is a greater
chance of physical contact, which means CWD could move more rapidly. "Based
on some computer models that we did at the Division of Wildlife, this scenario
could prove devastating," Miller says.
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- "The only preventive measure we can take is to cut
down the deer population in the infected areas. But these areas are popular
with hunters, so that would be controversial. As a result, right now we're
just checking for the disease, but unless something is done, CWD could
spread farther and farther east. I'm not saying that it'll be in New Jersey
next year, but in 10 or 15 years, who knows?"
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- So this article ends not with a climax, but with a "to
be continued." Many questions still surround what we hope is erroneously
named Mad Deer Disease. Consequently, we're left in the dark, speculating
as to what it means to deer, to hunting and to hunters.
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- ________
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- Campaign for Food Safety 6114 Hwy 61, Little Marais,
MN 55614 Activist or Media Inquiries: 218 226-4164 Fax 218 226-4157 Ronnie
Cummins <Ronnie@purefood.org
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